Optical isolator system and method

Abstract

An optical isolator system and method improving the manufacturability of the system, including fabricating a unitary tubular optical isolator system in two parts which are soldered together. The tubular system includes an internal disk to protect the isolator from heated solder during joinder of containment portions. The optical isolator system includes tubes to space polarizer, analyzer, and isolator portions.

What is claimed is: 
     
       1. An optical isolator system, including: a collimator including an input fiber with an exposed face angled in construction to avoid reverse reflection of optical signals initially directed in a first selected direction of an optical path,   a fiber holder having an output face planar coincident with the exposed face of the input fiber, said collimator including a non-reflective coating fabricated epitaxially on the joint coincident faces of said input fiber and fiber holder, and   a GRIN lens axially offset from said input fiber; an isolator including   a polarizer,   a rotator coaxial with and axially offset from said polarizer, and   a polarization analyzer axially offset from said rotator; and     a condenser including an output fiber with an exposed face angled in construction to avoid reverse reflection of optical signals initially directed in a selected direction of an optical path.   a fiber holder having an input face planar coincident with the exposed face of the output fiber, said condenser including a non-reflective coating fabricated epitaxially on the joint coincident faces of said output fiber and fiber holder, and   a GRIN lens axially offset from said output fiber; and a containment for axially securing said collimator, said isolator, and said condenser, and further includes a disk positioned axially between said isolator and said condenser and having an opening for passing optical signals from the isolator to the condenser.     
     
     
       2. The optical isolator system of claim 1 including a containment for axially securing said collimator, said isolator, and said condenser. 
     
     
       3. The optical isolator system according to claim 2 wherein said containment includes first and second portions which overlap in part to form an enclosure. 
     
     
       4. The optical isolator system according to claim 3 wherein said first and second portions are tubular. 
     
     
       5. The optical isolator system according to claim 4 wherein said first and second portions are soldered together. 
     
     
       6. The optical isolator system of claim 1, wherein said containment includes first and second portions which overlap in part to form an enclosure,   said first and second portions are soldered together, and   said disk prevents said solder from contacting said isolator.   
     
     
       7. The optical isolator system of claim 1 wherein the rotator comprises (BiYbTb)3Fe 5  O 12 . 
     
     
       8. A method of assembling an optical isolator system including a collimator, an isolator, and a condenser, in a two part tubular containment, the isolator including a polarizer, a rotator, and a polarization analyzer, comprising: fabricating epitaxially a non-reflective coating on faces of the collimator;   securing said collimator and isolator at respective first and second locations of a selected first portion of said two part tubular containment, securing said isolator including securing the polarizer, the rotator, and the polarization analyzer axially offset from each other at the second location of the selected first portion;   securing said condenser in said second portion of said two part tubular containment; and   axially securing said first and second two parts of said tubular containment to each other to form an enclosure, wherein said tubular containment further includes a disk positioned axially between said isolator and said condenser and having an opening for passing optical signals from the isolator to the condenser.   
     
     
       9. The method of claim 8 including soldering said first and second two parts of said tubular containment to each other to form an enclosure. 
     
     
       10. The method of claim 9 including protecting said isolator from solder during soldering. 
     
     
       11. An optical isolator system, including: a containment having first and second axial openings for connecting input and output optical fibers;   a collimator mounted in said containment including   an input fiber with an exposed face angled in construction to avoid reverse reflection of optical signals initially directed in a first selected direction of an optical path.   a fiber holder having an output face planar coincident with the exposed face of the input fiber, said collimator including a non-reflective coating deposited epitaxially on the joint coincident faces of said input fiber and said fiber holder, and   a GRIN lens axially offset from said input fiber;   an isolator mounted in said containment including a polarizer,   a rotator coaxial with and axially offset from said polarizer, and   a polarization analyzer axially offset from said rotator; and   a condenser mounted in said containment for receiving forward directed optical signals from said isolator; and a containment for axially securing said collimator, said isolator, and said condenser, and further includes a disk positioned axially between said isolator and said condenser and having an opening for passing optical signals from the isolator to the condenser.     
     
     
       12. An optical isolator system according to claim 11, said containment further including first and second tubular portions respectively including first and second flanges which overlap with each other. 
     
     
       13. An optical isolator system according to claim 12 further including a physical structure separating said isolator and said first and second flanges. 
     
     
       14. An optical isolator system according to claim 13 wherein said physical structure is annular. 
     
     
       15. An optical isolator system according to claim 13 wherein said first and second flanges are connected by solder. 
     
     
       16. An optical isolator system, including: a collimator including an input fiber with an exposed face angled in construction to avoid reverse reflection of optical signals initially directed in a first selected direction of an optical path,   a fiber holder having an output face planar coincident with the exposed face of the input fiber, and   a GRIN lens axially offset from said input fiber;     an isolator including a polarizer,   a rotator coaxial with and axially offset from said polarizer,   a polarization analyzer axially offset from said rotator, and   a permanent magnet in first and second axially offset portions, said polarizer being mounted in said first portion, and said polarization analyzer being mounted in said second portion;     a condenser including an output fiber with an exposed face angled in construction to avoid reverse reflection of optical signals initially directed in a selected direction of an optical path.   a fiber holder having an input face planar coincident with the exposed face of the output fiber, and     a GRIN lens axially offset from said output fiber; and a containment for axially securing said collimator, said isolator, and said condenser, and further includes a disk positioned axially between said isolator and said condenser and having an opening for passing optical signals from the isolator to the condenser.   
     
     
       17. A method of fabricating an optical system having a polarizer, an optical rotator, and a polarization analyzer, including: axially aligning in ordered sequence a polarizer, an optical rotator, and a polarization analyzer, each axially offset from each other   establishing magnetic operating conditions to said optical rotator to enable said optical system to permit optical transmission in one optical direction and to prevent optical transmission through said optical system in the opposite axial direction,   applying light from a laser light source to said polarizer in an axial direction and passing said light through said polarizer, said optical isolator, and said polarization analyzer,   measuring the level of light transmitted from said polarization analyzer, and   adjusting said polarization and polarization analyzers with respect to optical insertion loss and isolation, wherein said optical system further includes a first ring positioned axially between said rotator and said polarizer, and a second ring positioned axially between said rotator and said polarization analyzer.   
     
     
       18. The method of fabricating an optical system of claim 17, wherein said isolator is mounted to a base by an adhesive, the first and second rings being disposed to prevent such adhesive from being disposed between said rotator and said polarizer and between said rotator and said polarization analyzer.